The present technology is related to Lawful Interception applications dealing with the positioning of the targets.
With the current technology there are many different methods for positioning of a target for Lawful Interception.
The accuracy of the positioning result goes from the centre of a GSM, UMTS, LTE cell to very narrow areas, in case Mobile Positioning Systems, MPSs, are involved in the positioning operation and the most accurate capabilities, e.g. GPS, are available.
Nevertheless, in case the MPS is not available in the mobile network, the most accurate positioning result is the CGI, Global Cell Identity, which means the geo coordinates of the centre of the cell serving the target.
FIG. 1 is a block diagram of an exemplary Lawful Interception, LI, system and network 10 according to prior art. Said system and network comprises a number of entities. The exemplary LI system comprises a Law Enforcement Management Function, LEMF, 12 for requesting LI services of the LI system and collecting the intercepted information of Intercepting Access Point, IAP, nodes in the system. The system shall provide access to the intercepted Content of Communications, CC, and Intercept Related Information, IRI, of a target and services related to the target on behalf of one or more Law Enforcement Agencies, LEAs, 80. An intercept request, also denoted Request for LI activation or addWarrant message, is sent through a first Handover Interface, HI1, located between the Law Enforcement Management Function 12 and an Intercept Mediation and Delivery Unit, IMDU, 14 comprising a Mediation Function, MF, and an Administration Function, ADMF, 16. Said Mediation Function 16 and Administration Function generate based on said received request a warrant comprising said one or more target identities, and sends said warrant towards an Intercepting Access Point, IAP, 20 via an interface denoted X1_1. The IAP 20 may be connected to a node of a network, e.g. the Internet, a 3 GSM (third Generation Mobile Communications System), etc., from which it intercepts said Content of Communications and Intercept Related Information of a mobile target. Said CC and IRI are network related data. As reference to the standard model, see references [1], [2] and [3], the content of communication is intercepted in the IAP network node and it is based upon duplication of target communication payload without modification. In reference [3], the interfaces HI1 and HI2 is specified in more detail. The IAP sends IRI raw data via an interface X2 to a Delivery Function for IRI reporting, DF2, 22 and a Mediation Function of IRI, MF2, 24 that generates and delivers to a collection functionality a standardized IRI report based on the received IRI report. Said standardized IRI report is sent over a standardized interface HI2 to the LEMF 12. The IAP 20 also sends CC raw data via an interface X3 to a Delivery Function for CC reporting, DF3, 26 and a Mediation Function of IRI, MF3, 28 which generates and delivers to a collection functionality a standardized CC report based on the received CC report. Said standardized CC report is sent over a standardized interface HI3 to the requesting LEMF 12. The ADMF entity 16 controls and communicates with the Mediation Function and Delivery Function for IRI reporting, MF2/DF2, via the interface X1_2 and the Mediation Function and Delivery Function for CC, MF3/DF3, via the interface X_13.
Together with the delivery functions it is used to hide from the third generation (3G) IAPs that there might be multiple activations by different Lawful Enforcement Agencies on the same target.
The HI2 and HI3-interfaces represent the interfaces between the LEA and two delivery functions. The delivery functions are used:                to distribute the Intercept Related Information, IRI, to the relevant LEA(s) via HI2;        to distribute the Content of Communication, CC, to the relevant LEA(s) via HI3.        
According to known internet access services, all the IP streams related to a given target is intercepted and delivered as a whole session data flow regardless any service used within an interception session. If a LEA needs to access specific contents embedded in the whole session streams, it becomes necessary to do an appropriate post-processing of the intercepted data to find the data content of interest.
In the LI solution, the warrant data are stored in a source target database 30 of the mediation function 16 and, during the activation period, they are set on the IAPs 20 and stored in a target database in each IAP 20. The data are not stored in a persistent way in the target databases in the IAP's, i.e. they are lost in case of system shut-down.
One problem regarding target positioning is that in case the MPS is not available in the mobile network, there is no more precise positioning result available.